title: Performance characteristics of consensus approaches for small and minor paroxysmal nocturnal hemoglobinuria clone determination by flow cytometry.
abstract: BACKGROUND
  Evaluation of paroxysmal nocturnal hemoglobinuria (PNH) clones by flow cytometry (FCM) is not standardized and is associated with consistent inter-laboratory variability.
  
  
  METHODS
  In order to rule out the influence of particular approach in generating final results, we analyzed the performance characteristics of individual consensus strategies for small to intermediate (1%-20%) and minor (<1%) PNH clones within the white blood cell (WBC) and red blood cell (RBC) compartments with sensitivity up to 0.1%.
  
  
  RESULTS
  Coefficient of variation (CV) for precision/reproducibility analysis ranged from 0.67%/1.49% to 2.56%/3.09% for granulocytes, from 0.93%/3.09% to 7.76%/12.06% for monocytes and from 0.41%/4.73% to 6.53%/5.1% for RBCs. Coefficient of determination (r2) for linear regression analysis ranged from 0.95 to 0.99, Wilcoxon ranks test showed no statistically significant differences (p>0.05), Bland-Altman analysis demonstrated performance agreement with mean bias ranging from -0.18 to 1.24.
  
  
  CONCLUSIONS
  Our results confirmed very good performance characteristics for precision and reproducibility analysis, excellent correlation and favorable agreement between strategies, suggesting that reported inter-laboratory variability is related mainly to incorrect performance and/or insufficient experience with PNH testing by flow cytometry, rather than to relevant limitations of any particular approach.
authors.forename: Iuri
authors.initials: I
authors.lastname: Marinov
authors.forename: Martina
authors.initials: M
authors.lastname: Kohoutová
authors.forename: Vlasta
authors.initials: V
authors.lastname: Tkáčová
authors.forename: Adam
authors.initials: A
authors.lastname: Pešek
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Cermák
authors.forename: Petr
authors.initials: P
authors.lastname: Cetkovský
mesh_terms: D002999:Clone Cells / Q000473:pathology; D032921:Consensus; D005434:Flow Cytometry / Q000379:methods*; D006457:Hemoglobinuria, Paroxysmal / Q000097:blood / Q000473:pathology*; D006801:Humans; D016014:Linear Models; D017410:Practice Guidelines as Topic; D015203:Reproducibility of Results